| Renal cyst | |
|---|---|
| Other names | Kidney cysst |
 | |
| Renal cyst of the left kidney (hyperintense area) as shown on MRI. | |
| Specialty | Urology  |
A renal cyst is a fluid collection in or on the kidney. There are several types based on the Bosniak classification. The majority are benign, simple cysts that can be monitored and not intervened upon. However, some are cancerous or are suspicious for cancer and are commonly removed in a surgical procedure called nephrectomy.
Numerous renal cysts are seen in the cystic kidney diseases, which include polycystic kidney disease and medullary sponge kidney.